A comparison of methods of estimating lucerne population for monitoring persistence

1984 ◽  
Vol 24 (125) ◽  
pp. 174 ◽  
Author(s):  
GM Lodge ◽  
AC Gleeson
Keyword(s):  
Soil Surface ◽  
Plant Population ◽  
Spatial Distributions ◽  
Comparison Of Methods ◽  
Population Densities ◽  
Plant Populations ◽  
Steel Mesh ◽  
Crown Size

Two sowing rates, 4 and 12 kg/ha, and two sowing methods, broadcast and drilled into 18 cm rows, were used to give different population densities and spatial distributions of a semi-winter dormant lucerne, Condura 73 Brand, in mown dryland plots. Lucerne population in these plots was monitored for the first 12 months after sowing by either estimating the frequency of cells occupied by plants, using a 1 m2 steel mesh with a 10 cm x 10 cm or a 5 cm x 5 cm grid, or estimating plant population by taking crown counts at the soil surface. To estimate the true plant population for each sowing rate and method, plots were excavated regularly and plant tap roots counted. Crown counts consistently underestimated the true plant population over the range of 35-450 plants/m2. The underestimation was greater at the higher sowing rate. At populations greater than 150 plants/m2, frequency estimates were not sensitive to changes in plant numbers, but within the range of 20-80 plants/m2 they reliably reflected changes in plant populations. In a second experiment, six lucerne cultivars with a range of dormancy characteristics and crown structures were used to investigate the effect of crown size and type. Although crown counts underestimated (P<0.05) the actual plant population of a highly winter active, narrow-crown cultivar, there were no significant differences between cultivars in the number of plants or their frequency estimates.

The yield response of oilseed rape to plant population density

2015 ◽  
Vol 154 (2) ◽  
pp. 305-320 ◽  
Author(s):  
S. E. ROQUES ◽  
P. M. BERRY
Keyword(s):  
Population Density ◽  
Oilseed Rape ◽  
Field Experiments ◽  
Plant Population ◽  
Yield Response ◽  
Population Densities ◽  
Winter Oilseed Rape ◽  
Gross Margin ◽  
Plant Populations ◽  
The Uk

SUMMARYEight winter oilseed rape and two spring oilseed rape field experiments were performed in the UK in harvest years 2009–12. Each experiment consisted of at least one hybrid and one open-pollinated variety grown at five seed rates from 10 or 20 seeds/m2 to 160 or 200 seeds/m2. Linear plus exponential curves were used to describe the yield response to seed rate and to calculate economically optimal seed rates. Plant counts were then used to derive optimal plant population densities. These ranged from <10 to 39 plants/m2 for six winter oilseed rape experiments between 73 and >155 plants/m2 in two winter oilseed rape experiments with severe spring droughts, and from 47 to 65 plants/m2 for spring oilseed rape. Optimal plant population densities were lower for hybrid than for open-pollinated varieties, due to a combination of the higher cost of hybrid seed and, for some experimental sites, hybrid varieties compensating better for low plant populations. Across all sites, sowing winter oilseed rape at 30 seeds/m2 rather than common commercial rates of 70 seeds/m2 for hybrids and 100 seeds/m2 for open-pollinated varieties would have increased average gross margin by £29/ha. Sowing spring oilseed rape at 70 seeds/m2 rather than commonly used rates of 120 or 150 seeds/m2 would have increased average gross margin by £64/ha.

scholarly journals The response of Faba bean (Vicia faba L.) varieties as evaluated by varied plant population densities in the highlands of Arsi Zone, Southeastern Ethiopia

Bionatura ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 846-851
Author(s):  
Dereje Dobocha ◽  
Wogayehu Worku ◽  
Debela Bekela ◽  
Zenebe Mulatu ◽  
Fasil Shimeles ◽  
...  
Keyword(s):  
Population Density ◽  
Seed Yield ◽  
Faba Bean ◽  
Plant Population ◽  
Test Weight ◽  
Total Biomass ◽  
Population Densities ◽  
Plant Populations ◽  
Significant Difference ◽  
Plant Population Density

Field experiments were carried out in 2016 and 2017 cropping seasons under on-farm conditions in Lemuna Bilbilo District, Southeastern Ethiopia to evaluate the effects of three varieties Degaga, Gora, Moti, and six plant populations (10, 25 (control), 30,50, 70, and 90 plants m-2) on faba bean specific yield and yield components. The experiments were laid out in a randomized complete block design in split plot arrangement in which varieties were assigned to main plots and plant populations to subplots with three replications. The year combined analysis of data revealed that seed yield, total biomass yield and test weight of seed were significantly (p<0.05) affected by varieties and plant population densities m-2. The highest seed yield (4649, 4594 and 4162 kg ha-1) was obtained at 90,70 and 50 plant m-2 for Degaga, Moti and Gora varieties respectively but, no significant difference between control for Degaga and Moti varieties. The highest total biomass of 9 t ha-1 was recorded from the highest 90 plant population m-2 though not significantly different to the total biomass obtained from 70, 50 and 25 (control) plants m-2. Gora variety significantly recorded the highest test weight of seed (889.2g) than the rest Degaga and Moti varieties. In short, founded on studied agronomic parameters of faba bean, 25 plant population density m-2 was economically recommended for Degaga and Moti varieties whereas, 50 plant population density m-2 was for Gora variety.

Effects of Plant Population on Sole-crop Cassava in Sierra Leone

1978 ◽  
Vol 14 (3) ◽  
pp. 239-244 ◽  
Author(s):  
W. Godfrey-Sam-Aggrey
Keyword(s):  
Sierra Leone ◽  
Yield Components ◽  
Dry Matter ◽  
Weight Ratio ◽  
Land Plant ◽  
Plant Population ◽  
Root Weight ◽  
Plant Populations ◽  
Sole Crop ◽  
Yield And Yield Components

SUMMARYEffects of plant population on mean yield and yield components of 2-year sole cassava crops were studied on Njala upland soils of Sierra Leone in two experiments. Increasing plant population of multi-shoot Cocoa cassava over 7000/ha decreased all the parameters studied except top/root weight ratio, which increased. The observed effects were attributed to competition for environmental resources, since area of land/plant unit decreased as plant population increased. The relations between plant populations and yields of fresh root and cortex dry matter were asymptotic, indicating that the respective yields were products of the vegetative phase of cropping.

scholarly journals Effects of population density on cauliflower crop (Brassica oleracea L. var. botrytis)

1981 ◽  
Vol 38 (1) ◽  
pp. 1-10
Author(s):  
Keigo Minami ◽  
Ricardo Victoria Fº
Keyword(s):  
Population Density ◽  
Brassica Oleracea ◽  
Plant Population ◽  
Population Densities ◽  
Plant Population Density ◽  
Brassica Oleracea L ◽  
Quality Weight

An experiment was carried out to study the effects of the following population densities cauliflowers (plants per ha): 20,833 (0.60 m x 0.80 m), 25,641 (0.60 m x 0.65 m), ....37.037 (0.60 m x 0.45 m) , 55.555 (.0.60 m x 0.30 m), and 111,111 (0,60 m x 0,15 m) ; variety Snow ball. It was concluded that the effects of plant population density are greater on curd quality (weight and size) than on production per ha. The best plant population density to produce cauliflowers curd for Brazil market is from 20,000 to 25,000 plants/ha while for mini-curd is above 55,000 plants/ha.

Low crop plant population densities promote pollen-mediated gene flow in spring wheat (Triticum aestivum L.)

2009 ◽  
Vol 18 (6) ◽  
pp. 841-854 ◽  
Author(s):  
Christian J. Willenborg ◽  
Anita L. Brûlé-Babel ◽  
Rene C. Van Acker
Keyword(s):  
Triticum Aestivum ◽  
Gene Flow ◽  
Spring Wheat ◽  
Triticum Aestivum L ◽  
Plant Population ◽  
Crop Plant ◽  
Population Densities

A comparison of methods for estimating plant population size

2018 ◽  
Vol 27 (8) ◽  
pp. 2021-2028 ◽  
Author(s):  
Christoph Reisch ◽  
Christoph Schmid ◽  
Florian Hartig
Keyword(s):  
Population Size ◽  
Plant Population ◽  
Comparison Of Methods ◽  
Plant Population Size

Grain Yield Gains and Associated Traits in Tropical X Temperate Maize Germplasm Under High and Low Plant Density

2021 ◽  
Author(s):  
Vince Ndou ◽  
Edmore Gasura ◽  
Pauline Chivenge ◽  
John Derera
Keyword(s):  
Population Density ◽  
Grain Yield ◽  
Plant Density ◽  
Plant Population ◽  
Population Densities ◽  
Genetic Gains ◽  
Maize Germplasm ◽  
High Plant Density ◽  
Number Of Leaves ◽  
Plant Population Density

Abstract Development of ideal breeding and crop management strategies that can improve maize grain yield under tropical environments is crucial. In the temperate regions, such yield improvements were achieved through use of genotypes that adapt high plant population density stress. However, tropical germplasm has poor tolerance to high plant population density stress, and thus it should be improved by temperate maize. The aim of this study was to estimate the genetic gains and identify traits associated with such gains in stable and high yielding temperate x tropical hybrids under low and high plant population densities. A total of 200 hybrids derived from a line x tester mating design of tropical x temperate germplasm were developed. These hybrids were evaluated for grain yield and allied traits under varied plant population densities. High yielding and stable hybrids, such as 15XH214, 15XH215 and 15XH121 were resistant to lodging and had higher number of leaves above the cob. The high genetic gains of 26% and desirable stress tolerance indices of these hybrids made them better performers over check hybrids under high plant population density. At high plant population density yield was correlated to stem lodging and number of leaves above the cob. Future gains in grain yield of these hybrids derived from temperate x tropical maize germplasm can be achieved by exploiting indirect selection for resistance to stem lodging and increased number of leaves above the cob under high plant density conditions.

scholarly journals Plant population and soil origin effects on rhizosphere nematode community composition of a range-expanding plant species and a native congener

Oecologia ◽  
2020 ◽  
Vol 194 (1-2) ◽  
pp. 237-250
Author(s):  
Rutger A. Wilschut ◽  
Kim J. H. Magnée ◽  
S. Geisen ◽  
W. H. van der Putten ◽  
O. Kostenko
Keyword(s):  
Plant Species ◽  
Plant Population ◽  
Enemy Release ◽  
Native Range ◽  
Centaurea Stoebe ◽  
Plant Populations ◽  
Range Theory ◽  
Dispersal Abilities ◽  
Population Effects ◽  
Root Feeding

Abstract Climate change causes species range expansions to higher latitudes and altitudes. It is expected that, due to differences in dispersal abilities between plants and soil biota, range-expanding plant species will become associated with a partly new belowground community in their expanded range. Theory on biological invasions predicts that outside their native range, range-expanding plant species may be released from specialist natural enemies, leading to the evolution of enhanced defence against generalist enemies. Here we tested the hypothesis that expanded range populations of the range-expanding plant species Centaurea stoebe accumulate fewer root-feeding nematodes than populations from the original range. Moreover, we examined whether Centaurea stoebe accumulates fewer root-feeding nematodes in expanded range soil than in original range soil. We grew plants from three expanded range and three original range populations of C. stoebe in soil from the original and from the new range. We compared nematode communities of C. stoebe with those of C. jacea, a congeneric species native to both ranges. Our results show that expanded range populations of C. stoebe did not accumulate fewer root-feeding nematodes than populations from the original range, but that C. stoebe, unlike C. jacea, accumulated fewest root-feeding nematodes in expanded range soil. Moreover, when we examined other nematode feeding groups, we found intra-specific plant population effects on all these groups. We conclude that range-expanding plant populations from the expanded range were not better defended against root-feeding nematodes than populations from the original range, but that C. stoebe might experience partial belowground enemy release.

scholarly journals Sowing operation direction and population densities in corn growing

2019 ◽  
Vol 23 (3) ◽  
pp. 183-187
Author(s):  
Rafael D. G. Corrêa ◽  
Carlos E. A. Furlani ◽  
Cristiano Zerbato ◽  
Danilo T. de Oliveira ◽  
Rafael H. de F. Noronha ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Photosynthetically Active Radiation ◽  
Corn Yield ◽  
Population Densities ◽  
Plant Populations ◽  
Hybrid Corn ◽  
Active Radiation ◽  
Plant Densities ◽  
Lower Plant ◽  
East West

ABSTRACT Among the factors that may influence corn yield are sowing operation direction and plant population, since they alter the shade index between crop rows, and consequently the efficiency of interception of the photosynthetically active radiation by the leaves of plants. The aim of this study was to evaluate the influence of sowing direction and plant populations on P2830VYH hybrid corn yield. The experiment was conducted at the facilities of FCAV-UNESP, latitude 21º 14’ S and longitude 48º 16’ W in Jaboticabal (SP). The treatments were composed of three sowing directions (North-South, Northeast-Southwest, and East-West) and three population densities (40,000, 60,000 and 80,000 plants ha-1). The treatment with 80,000 plants ha-1 had the lowest cost per sack of corn and profitability 21% higher than that of the treatment with 60,000 plants ha-1, and 45% higher than that of the treatment with 40,000 plants ha-1. Sowing direction had no influence on grain yield when environmental conditions were favorable to the development of the crop. Lower plant densities lead to higher individual results in relation to the number of cobs, length of cobs and number of grains per row.

The influence of inter-row spacing and plant population on the yield of peanuts at Katherine, N.T

1962 ◽  
Vol 2 (4) ◽  
pp. 54 ◽  
Author(s):  
LJ Phillips ◽  
MJT Norman
Keyword(s):  
Plant Population ◽  
Row Spacing ◽  
Clay Loam ◽  
Plant Populations ◽  
Kernel Yield ◽  
Multifactorial Experiment

In 1957-58 and 1958-59, Virginia Bunch and Natal Common peanuts were sown on Tippers clay loam at Katherine, N.T., in a multifactorial experiment at two inter-row spacings (2 ft and 3 ft), four plant populations (10, 20, 40 and 80 thousand per acre) and two dates. In 1960-61, Natal Common only was sown at the same inter-row spacings, at two dates, and at populations of 10, 20, 30 and 40 thousand per acre. Over two seasons, the yield of Virginia Bunch kernels was not significantly influenced by variation in population, though the yield of hay was 42 per cent higher at 80,000 plants per acre than at 10,000 plants per acre. Kernel yields from 2 f t rows were 14 per cent higher than from 3 f t rows. In the first two seasons, the yield of Natal Common kernels was lower at 80,000 plants per acre than at 40,000 plants per acre. Over three seasons, maximum kernel and h g yields were achieved at 40,000 plants per acre ; the kernel yield at this population was 35 per cent greater than at 10,000 plants per acre. With early-planted Natal Common, 2.ft rows gave an 11 per cent higher yield of kernels than 3 f t rows, but with later planting there was no significant effect of inter-row spacing. The optimum economic seeding rates were estimated approximately as 30 lb an acre for Virginia Bunch and 45 lb an acre for Natal Common.

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